Cholesterol Accumulation as a Driver of Hepatic Inflammation Under Translational Dietary Conditions Can Be Attenuated by a Multicomponent Medicine.

Background: Non-alcoholic fatty liver disease (NAFLD) is a complex multifactorial disorder that is characterised by dysfunctional lipid metabolism and cholesterol homeostasis, and a related chronic inflammatory response. NAFLD has become the most common cause of chronic liver disease in many countries, and its prevalence continues to rise in parallel with increasing rates of obesity. Here, we evaluated the putative NAFLD-attenuating effects of a multicomponent medicine consisting of 24 natural ingredients: Hepar compositum (HC-24).
Methods: Ldlr-/-.Leiden mice were fed a high-fat diet (HFD) with a macronutrient composition and cholesterol content comparable to human diets for 24 weeks to induce obesity-associated metabolic dysfunction, including hepatic steatosis and inflammation. HC-24 or vehicle control was administered intraperitoneally 3 times/week (1.5 ml/kg) for the last 18 weeks of the study. Histological analyses of liver and adipose tissue were combined with extensive hepatic transcriptomics analysis. Transcriptomics results were further substantiated with ELISA, immunohistochemical and liver lipid analyses.
Results: HFD feeding induced obesity and metabolic dysfunction including adipose tissue inflammation and increased gut permeability. In the liver, HFD-feeding resulted in a disturbance of cholesterol homeostasis and an associated inflammatory response. HC-24 did not affect body weight, metabolic risk factors, adipose tissue inflammation or gut permeability. While HC-24 did not alter total liver steatosis, there was a pronounced reduction in lobular inflammation in HC-24-treated animals, which was associated with modulation of genes and proteins involved in inflammation (e.g., neutrophil chemokine Cxcl1) and cholesterol homeostasis (i.e., predicted effect on 'cholesterol' as an upstream regulator, based on gene expression changes associated with cholesterol handling). These effects were confirmed by CXCL1 ELISA, immunohistochemical staining of neutrophils and biochemical analysis of hepatic free cholesterol content. Intrahepatic free cholesterol levels were found to correlate significantly with the number of inflammatory aggregates in the liver, thereby providing a potential rationale for the observed anti-inflammatory effects of HC-24.
Conclusions: Free cholesterol accumulates in the liver of Ldlr-/-.Leiden mice under physiologically translational dietary conditions, and this is associated with the development of hepatic inflammation. The multicomponent medicine HC-24 reduces accumulation of free cholesterol and has molecular and cellular anti-inflammatory effects in the liver.
Competing Interests: AMu and BS are employees of Heel GmbH. NK and YB are former employees of Heel GmbH. Heel GmbH was involved in the design of the study and the preparation of the manuscript. Heel GmbH was not involved in data acquisition or data analysis. The publication of this study was a requirement of the funding received from Health~Holland, Top Sector Life Sciences & Health. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2021 Mueller, Kleemann, Gart, van Duyvenvoorde, Verschuren, Caspers, Menke, Krömmelbein, Salic, Burmeister, Seilheimer and Morrison.)